Silicon Carbide (SiC) is a desirable material for high-power and high-temperature semiconductor devices due to its high breakdown field, high thermal conductivity, and wide bandgap. However, to take advantage of the high breakdown field in a high-voltage device, an efficient edge termination is needed. More specifically, field crowding at the edge of the device results in device breakdown at the edge of the device, which in turn decreases the blocking voltage of the device well below the ideal blocking voltage (i.e., the blocking voltage of the ideal parallel-plane device).
Field crowding has traditionally been addressed using an ion implanted or etched Junction Termination Extension (JTE). More specifically, the JTE includes a thin ion implanted or etched region of a lighter doping than a main junction of the semiconductor device, and the doping type of the JTE is opposite that of a drift layer of the semiconductor device. A typically etched JTE that includes three etched steps is illustrated in FIG. 1. The etched steps progressively reduce a dose (i.e., a doping concentration multiplied by the height dimension) of a corresponding P type layer from a main junction of the semiconductor device to an edge of a corresponding edge termination region. This in turn leads to a decrease in the total electric field towards the edge of the edge termination region. However, due to the etched steps, peaks are present in a lateral, or x, component of the total electric field. These peaks place high stress on dielectrics and packaging materials formed on the surface of the semiconductor device, which can lead to failure of the semiconductor device. Thus, there is a need for an improved edge termination structure.